I wonder why the flight deck stopped so far short of the bow.
Its due to design differences. In the USN, the use of arresting gear allowed a higher aircraft recovery rate. An aircraft would land, the barrrier would be lowered and the aircraft would taxi forward to either be lowered on the elevator or be pushed toward the bow. Aircraft had to be pushed toward the bow because they could be recovered faster than the elevator could cycle. This method allowed the practical use of a large airgroup.
The RN did not use arresting gear early on. They let the landing aircraft roll to a stop on the flight deck. The raised forward section of the flight deck of these ships was due to the need to have a ramp or incline that would help bring an aircraft to a halt, if necessary. After the aircraft stopped, it was taken to the elevator and struck below. Only then was the next aircraft allowed to land. Needless to say, this required a considerable amount of time. It also made the use of large airgroups impractical.
Due to the long recovery times, the RN had a need to launch fighters and recover strike aircraft at the same time. That's why their early carriers have the lower launching ramp/deck. The need to provide sufficient clearance for the launching fighter on the lower deck required that the upper flight deck stop early in the fighters take-off run. Also, the fine lines of the battlecruiser bow wouldn't allow the flight deck to run all the way to the bow (probably about as far as the bow 4-inch mount in the 1943 drawing) without causing considerable trimming by the bow.